1. Field of the Invention
This invention relates to a miniature counter reset to zero by a push button, and more particularly to a miniature counter especially suitable to be utilized in combination with a tape recorder or similar device.
2. Description of the Prior Art
The push button zero reset type counter is well known in the art and is frequently incorporated into various devices for controlling and displaying numberical data generated by the devices. It is desirable to miniaturize the counter as the size of the devices incorporated with the counter becomes smaller. Various constructions and configurations of counters have been proposed to meet this requirement. However, since prior art counters are not completely satisfactory in all applications, it has become desirable to provide a compact counter with a protective cover which is capable of providing performance equivalent to larger scale prior art counters and which displays information which even though small in size can easily be read.
U.S. Pat. No. 3,963,903, for example, discloses a counter comprising a counter frame disposed above a group of digit wheels, a numerical data read unit mounted on the frame, and a cover. This counter is not of the push button reset type and the characters are small and difficult to read.
Another prior art counter is disclosed in U.S. Pat. No. 3,286,916. This counter is also not of the push button reset type and has lenses for magnifying the displayed characters formed on the inner surface of a cover at positions corresponding to the positions on the digit wheels to be displayed.
An electromagnetic counter similar to these is disclosed in U.S. Pat. No. 3,725,648, in which a convex lens is integrally formed into the surface of the cover. The covers disclosed in U.S. Pat. Nos. 3,963,903 and 3,286,916 merely comprise glass plates fitted in the front ends of cylindrical casings which are independent of the counter frame. This configuration limits miniaturization. However, in the electromagnetic counter disclosed in U.S. Pat. No. 3,725,648, the cover is constructed to also act as a casing for the counter. Since the flange of the cover is secured to the base by screws, it is impossible to significantly miniaturize the construction.
It is also desirable to provide a push button zero reset type counter in which the combination of digit wheels can be altered to change the display position. With the prior art counters previously discussed, it is necessary to change the design to meet this goal. One method which has been tried is the push button zero reset type counter disclosed in Japanese Utility Model Publication No. 5070 of 1972. In this counter, pinions or press members which are invisible from the read position are operated, in conjunction with heart-shaped cams placed rigidly on the same shaft as the digit wheels, to rotate the digit wheels. However, if the pinions or press members are disposed along one side of the digit wheels the press members would extend between the bottom plates of the frame at positions below the digit wheels. With this construction, it is necessary to provide sufficient space between the digit wheels and the bottom frame plates to assure proper operation of the press members as they engage the heart-shaped cams. The dimensions of this space are determined by the space necessary to ensure positive engagement between the end of each press member and its respective heart-shaped cam until a digit wheel disengages a pinion, the difference between the levels of the high point and the low point of the heart-shaped cam, and the height of the press member. However, the idle space and the difference in the levels constitute a dead space which does not contain any component element of the counter, thus hindering the miniaturization of the counter.